Doubtly
@Doubtly · Joined Feb 2021
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- Explain how the element sodium is monovalent. Sodium is a metal which has atomic number 11. It has 1 electron in its last shell which means it has 1 valence electron. In order to get sta... 1
- Write the steps in deducing the chemical formulae of the following compounds. (v) Aluminium hydroxide Aluminium hydroxide : Step 1 : Write the symbols and valencies of the radicals. Symbols Al OH Valency 3 1 Step 2 : Cross-multiply symbols of... 1
- Write the steps in deducing the chemical formulae of the following compounds. (iv) Calcium oxide Calcium oxide : Step 1 : Write the symbols and valencies of the radicals. Symbols Ca O Valency 2 2 Step 2 : Cross-multiply symbols of radica... 1
- Write the steps in deducing the chemical formulae of the following compounds. (iii) Ferric phosphate Ferric phosphate : Step 1 : Write the symbols and valencies of the radicals. Symbols Fe PO₄ Valency 3 3 Step 2 : Cross-multiply symbols of r... 1
- Write the steps in deducing the chemical formulae of the following compounds. (ii) Potassium nitrate, Potassium nitrate : Step 1 : Write the symbols and valencies of the radicals. Symbols K NO₃ Valency 1 1 Step 2 : Cross-multiply symbols of r... 1
- Write the steps in deducing the chemical formulae of the following compounds. Sodium sulphate Sodium sulphate : Step 1 : Write the symbols and valencies of the radicals. Symbols Na SO₄ Valency 1 2 Step 2 : Cross-multiply symbols of ra... 1
- Write symbols of the following elements and the radicals obtained from them and indicate the charge on the radicals. Element Symbols Charge 1. Mercury Hg Mercurous- Hg⁺ 2. Potassium K Potassium- K⁺ 3. Nitrogen N Azide- N₃⁻ 4. Copper Cu Cuprous- Cu⁺ 5. Sulph... 2
- Give example Trivalent basic radicals Trivalent Basic Radical : (i) Al^(3+ ) (ii) Cr³⁺ (iii) Fe³⁺ (iv) Au³⁺ 1
- give example Bivalent acidic radicals Bivalent Acidic Radical : (i) S^(2- ) (ii) O^(2- ) (iii) Se^(2- ) 2
- Give example Metals with variable valency Metal With Variable Valency : (i) Cu → Cu^(+ )Cu²⁺, (ii) Hg → Hg⁺, Hg²⁺ (iii) Fe → Fe²⁺ , Fe³⁺ 1
- Give example Composite radicals Composite Radical : (i) SO₄^( 2- ) (ii) H₃O⁺ (iii) NH₄^(+ ) (iv) HCO₃^(- ) (v) SO₄^(2- ) (vi) NO₄⁻ 2
- Give examples Basic radicals Basic Radical : (i) Na⁺ (ii) Fe²⁺ (iii) Ag⁺ (iv)^( )Al³⁺ (v) Cr³⁺ (vi) Sn²⁺ 2
- Give examples. Positive ions Positive ions : (i) Sodium Ions Na⁺ (ii) Silver ions Ag⁺ (iii) Aluminium ions^( )Al^(3+ ), (iv) Chromium ion Cr³⁺ (v) Calcium ion Ca²⁺ 1
- Why are fuse wires used? Used to protect domestic appliances, fuse wire has specific melting point and is made of a mixture of substances. It is connected in series... 1
- Explain Ohm’s law with the formula. George Simon Ohm, a German Scientist put across a law known as Ohm’s law, from which the relationship between the current flowing through a... 1
- What are free electrons? Free electrons are the one or more outer shell electrons found in every atom of a metallic conductor, which are bound weakly to the nucleus.... 1
- If a charge of 420 C flows through a conducting wire in 5 minutes what is the value of the current? Current flowing through the conducting wire is I= Charge(Q)/Time (t) ⇒I=420/(5×60)=420/300=1.4 A Hence, the current flowing through the wire... 1
- When two resistors are connected in series, their effective resistance is 80 Ω. When they are connected in parallel, Let the two resistances be R₁ and R₂. Therefore, R₁ + R_(2 )= 80 Ω or, R_(1 )= 80 −R₂-R₂ .....(i) and 1/R₁+1/R₂=1/20 ⇒R₁R₂=20(R₁+R₂) As, R₁=... 1